Should Your Child See a Doctor?

Infection Exposure Questions – Contagiousness

Definition

This topic includes information about the transmission of common infections, including how long to stay out of school or daycare

Incubation Period:
Time interval between exposure to the infection and onset of symptoms.

Contagious Period:
Time interval during which a sick child's disease is contagious to others. With precautions, children sometimes can return to day care and school before this period is over.

Infections that are not Contagious:
Many common bacterial infections are not contagious (e.g., ear infections, sinus infections, bladder infections, kidney infections, and pneumonia). Sexually transmitted diseases are not contagious to children unless there is sexual contact or shared bathing.

Infection Exposure Table

DISEASE

INCUBATION PERIOD
(DAYS)

CONTAGIOUS PERIOD
(DAYS)

Skin Infections/Rashes:

Chickenpox

10-21

2 days before rash until all sores have crusts (6 - 7days)

Fifth disease (Erythema infectiosum)

4-14

7 days before rash until rash begins

Hand, foot, and mouth disease

3-6

Onset of mouth ulcers until fever gone

Impetigo (strep or staph)

2-5

Onset of sores until 24 hours on antibiotic

Lice

7

Onset of itch until 1 treatment

Measles

8-12

4 days before rash until 4 days after rash appears

Roseola

9-10

Onset of fever until rash gone (2 days)

Rubella (German measles)

14-21

7 days before rash until 5 days after rash appears

Scabies

30-45

Onset of rash until 1 treatment

Scarlet fever

3-6

Onset of fever or rash until 24 hours on antibiotic

Shingles (contagious for chicken pox)

14-16

Onset of rash until all sores have crusts (7 days) (Note: No need to isolate if sores can be kept covered.)

Warts

30-180

Minimally contagious

Respiratory Infections:

Bronchiolitis

4-6

Onset of cough until 7 days

Colds

2-5

Onset of runny nose until fever gone

Cold sores (herpes)

2-12

Footnote 1

Coughs (viral) or croup (viral)

2-5

Onset of cough until fever gone

Diphtheria

2-5

Onset of sore throat until 4 days on antibiotic

Influenza

1-2

Onset of symptoms until fever gone

Sore throat, strep

2-5

Onset of sore throat until 24 hours on antibiotic

Sore throat, viral

2-5

Onset of sore throat until fever gone

Tuberculosis

6-24 months

Until 2 weeks on drugs (Note: Most childhood TB is not contagious.)

Whooping cough

7-10

Onset of runny nose until 5 days on antibiotic

Intestinal Infections:

Diarrhea, bacterial

1-5

Footnote 2 for Diarrhea Precautions

Diarrhea, giardia

7-28

Footnote 2 for Diarrhea Precautions

Diarrhea, traveler's

1-6

Footnote 2 for Diarrhea Precautions

Diarrhea, viral (Rotavirus)

1-3

Footnote 2 for Diarrhea Precautions

Hepatitis A

14-50

2 weeks before jaundice begins until jaundice resolved (7 days)

Pinworms

21-28

Minimally contagious, staying home is unnecessary

Vomiting, viral

2-5

Until vomiting stops

Other Infections:

Infectious mononucleosis

30-50

Onset of fever until fever gone (7 days)

Meningitis, bacterial

2-10

7 days before symptoms until 24 hours on IV antibiotics in hospital

Mumps

12-25

5 days before swelling until swelling gone (7 days)

Pinkeye without pus (viral)

1-5

Mild infection, staying home is unnecessary

Pinkeye with pus (bacterial)

2-7

Onset of pus until 1 day on antibiotic eyedrops

Notes

Cold sores:
Less than 6 years old, contagious until cold sores are dry (4-5 days). No isolation if sores are on part of body that can be covered. More than 6 years old, no isolation necessary if beyond touching, picking stage.

Diarrhea Precautions:
Contagious until stools are formed. Stay home until fever is gone, diarrhea is mild, blood and mucus are gone, and toilet-trained child has control over loose BMs. Shigella and E-coli 0157 require extra precautions. Consult your day care provider regarding attendance restrictions.

Disclaimer:
This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.

Author and Senior Reviewer: Barton D. Schmitt, M.D.

Last Reviewed: 1/19/2009

Last Revised: 11/18/2006

Copyright 1994-2009 Barton D. Schmitt, M.D.

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